Combine the bourbon, liqueur, vermouth, and a splash of bitters in a cocktail shaker over ice and stir or shake to chill. Strain into a chilled martini glass, garnish with a cherry if desired, and enjoy.

Note:  At the restaurant, we combine the bourbon and liqueur in an oak barrel for aging. If you have a small aging barrel at home, you can combine the bourbon and liqueur (in the correct proportions), and age for up to 1 month before making this cocktail at home.